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While the Internet offers a host of ways to communicate with friends, co-workers and even complete strangers, it also allows third-parties to snoop on those communications, as well as track your online conversations and activities. Using encryption tools can help you keep your communications secret, whether you are swapping personal tales with a friend or transacting important business with a client.

Eavesdropping on the Internet

Whenever you transmit data across the Internet, that information is broken up into discrete “packets” which then flow from computer to computer, guided across the network to their intended target. While this distributed navigation system ensures that packets have many different ways to get from point "A" to point "B" in the case of network interruptions, it also means that any computer along the way can snoop on packets that pass through its hands.

Symmetrical Encryption

One way around this problem is using a symmetrical encryption system. This involves a single cryptographic key, known to both parties, that can encrypt and decrypt information. One example of an extremely simple symmetric key is replacing letters with numbers -- 1 for "A," 2 for "B" and so on. As long as both parties know the key, they can send secure messages back and forth. This requires a secure method for sharing the key in the first place, something that may not be possible when communicating across the Internet.

Public Key Encryption

Most encryption schemes on the Internet use a system known as public key encryption. This system involves a special pair of keys -- one public and one private -- for each user, so that a user encodes messages using this pair of keys, and the other user has the opposing pair of keys for decoding the messages. For example, one user encodes a message with his private key and his correspondent’s public key, and that correspondent then decodes the message with her private key and the sender’s public key. This ensures that no one but the two users can gain access to the encrypted data.

SSL/TLS

Public key encryption lies at the heart of Secure Sockets Layer, which is another common form of encryption on the Internet. In an SSL connection, your computer and the target computer take the roles of the two correspondents described in Section 3, swapping public keys and encoding all data that travels back and forth between the two machines. This ensures that file transfers and other communications remain secure, although outsiders may still be able to determine the nature of the transfer by looking at public packet information -- a packet’s destination port, for example, may give away the type of transfer, as most Internet protocols use easily identifiable port numbers. The Transport Layer Security, or TLS, protocol is SSL's successor, although many users and programs refer to any such encrypted connection simply as "SSL."

About the Author

Milton Kazmeyer has worked in the insurance, financial and manufacturing fields and also served as a federal contractor. He began his writing career in 2007 and now works full-time as a writer and transcriptionist. His primary fields of expertise include computers, astronomy, alternative energy sources and the environment.